Emissions Cleaning Module and a Method of Cleaning a Particulate Filter

ABSTRACT

An emissions cleaning module includes a first conduit including an inlet and an outlet and containing a particulate filter; a second conduit including an inlet and an outlet; and an end coupling fluidly connecting the outlet of the first conduit to the inlet of the second conduit. The end coupling is provided with a cleaning port including a cover which closes an aperture in the end coupling. Providing the cleaning port in the end coupling fluidly connecting the outlet of the first conduit to the inlet of the second allows for improved access and cleaning of the emissions cleaning module.

TECHNICAL FIELD

The disclosure relates to an apparatus for cleaning fluids emitted during the operation of combustion engines.

BACKGROUND

Engines, for example IC engines burning gasoline, diesel or biofuel, output various harmful substances which must be treated to meet current and future emissions legislation. Most commonly those substances comprise hydrocarbons (HC), carbon monoxides (CO), mono-nitrogen oxides (NO_(x)) and particulate matter, such as carbon (C), a constituent of soot. Some of those substances may be reduced by careful control of the operating conditions of the engine, but usually it is necessary to provide an emissions cleaning module downstream of the engine to treat at least some of those substances entrained in the exhaust gas. Various apparatus for reducing and/or eliminating constituents in emissions are known. For example, it is known to provide an oxidation device, such as a diesel oxidation catalyst, to reduce or to eliminate hydrocarbons (HC) and/or carbon monoxide (CO). Oxidation devices generally include a catalyst to convert those substances into carbon dioxide and water, which are significantly less harmful. As a further example, emissions cleaning modules may include a particulate filter to restrict the particulates present in the exhaust gas from being output to atmosphere.

By use of an emissions cleaning module, engine emissions can be cleaned, meaning that a proportion of the harmful substances which would otherwise be released to atmosphere are instead converted to carbon dioxide (CO₂), nitrogen (N₂) and water (H₂O).

The residue, such as soot, collected in a particulate filter must be removed from time to time to maintain the efficiency of the particulate filter. One method by which residue, such as soot, may be removed from the particulate filter is referred to as regeneration, in which the temperature of the particulate filter is raised so that the residue, such as soot, is burned off the particulate filter. However, this results in ash being deposited in the particulate filter, which may need to be removed during the life of the emissions cleaning module.

It is also known to use a physical cleaning technique, such as flushing with compressed air, to clean a particulate filter. U.S. Pat. No. 6,632,406 describes a pollution removing device having a relatively small service port downstream of a particulate filter. Compressed air may be injected into the service port to attempt to flush residue from the particulate filter.

It is desirable for an emissions cleaning module to have a compact size in order to minimise the space taken up in a vehicle. However, using a compact geometry may result in difficulties in using physical cleaning techniques for the cleaning of a particulate filter.

Against this background there is provided an emissions cleaning module and method of cleaning a particulate filter of a residue.

SUMMARY OF THE DISCLOSURE

The present disclosure provides an emissions cleaning module comprising:

-   -   a first conduit comprising an inlet and an outlet and containing         a particulate filter;     -   a second conduit comprising an inlet and an outlet; and     -   an end coupling fluidly connecting the outlet of the first         conduit to the inlet of the second conduit;     -   wherein the end coupling is provided with a cleaning port         comprising a cover which closes an aperture in the end coupling.

The present disclosure also provides a method of cleaning a particulate filter housed in an emissions cleaning module, the emissions cleaning module comprising:

-   -   a first conduit comprising an inlet and an outlet and containing         the particulate filter;     -   a second conduit comprising an inlet and an outlet; and     -   an end coupling at least partially fluidly connecting the outlet         of the first conduit to the inlet of the second conduit;     -   the method comprising the steps of:         -   a) providing a cleaning port in the end coupling;         -   b) opening the cleaning port;         -   c) inputting a cleaning fluid through the cleaning port into             contact with an end face of the particulate filter;         -   d) recovering residue from the particulate filter; and         -   e) closing the cleaning port.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 shows an emissions cleaning module in accordance with the present disclosure;

FIG. 2 shows a support frame of the emissions cleaning module of FIG. 1;

FIG. 3 shows a cleaning port of the emissions cleaning module of FIG. 1;

FIG. 4 shows the cleaning port of FIG. 3 from another angle;

FIG. 5 shows a cross-sectional view through the cleaning port of FIG. 3;

FIG. 6 shows a cross-sectional view through the cleaning port of FIG. 3 with a cover of the cleaning port removed.

DETAILED DESCRIPTION

An emissions cleaning module 1 is illustrated in FIG. 1.

The emissions cleaning module 1 comprises a first conduit 10 and a second conduit 20. A third conduit 30 and a support structure 40 may also be present. The support structure 40 may comprise a first support member 50 and a second support member 60.

Each support member 50, 60 may be generally planar and may be of rigid material, for example metal.

The first, second and third conduits 10, 20, 30 may be elongate, having an axis of elongation, and may have substantially constant cross-section along the axis of elongation. The first, second and third conduits 10, 20, 30 may be substantially cylindrical.

The first conduit 10 comprises a first end 11 providing an inlet to the conduit and a second end 12 providing an outlet to the conduit. The second conduit 20 comprises a first end 21 providing an outlet to the conduit and a second end 22 providing an inlet to the conduit.

The third conduit 30 may comprise a first end 31 providing an inlet to the conduit and a second end providing an outlet to the conduit.

The conduits 10, 20, 30 may extend between the support members 50, 60. The conduits 10, 20, 30 may be generally substantially parallel. The first ends 11, 21, 31 of the first, second and third conduits 10, 20, 30 may be received in and may be shaped to correspond with first, second and third openings 51, 52, 53, respectively, of the first support member 50. The second ends 12, 22 of the first, second and third conduits 10, 20, 30 may be received in and may be shaped to correspond with first, second and third openings 61, 62, 63, respectively, of the second support member 60. By this arrangement, lateral movement of the conduits may be restricted.

As shown in FIG. 2, each opening 51, 52, 53, 61, 62, 63 may comprise a flange 51 a, 52 a, 53 a, 61 a, 62 a, 63 a extending around a perimeter of the opening. Each support member 50, 60 may further comprise an inwardly turned lip 59, 69 extending at least part way around a periphery of the support member 50, 60.

The conduits 10, 20, 30 may all be of substantially similar length. The first conduit 10 may have a first diameter, the second conduit 20 may have a second diameter and the third conduit 30 may have a third diameter. The second diameter may be smaller than the first and third diameters.

The first and second ends 11, 21, 31, 12, 22 of the conduits 10, 20, 30 may be welded, adhered or otherwise secured to portions of the support members 50, 60 defining or surrounding the openings. Alternatively, first and second ends 11, 21, 31, 12, 22, of the conduits 10, 20, 30 may abut the inner sides of the support members 50, 60 so as to overlie respective openings in the support members 50, 60.

The first, second and third conduits 10, 20, 30 and the first and second support members 50, 60 may be interconnected in a manner which restricts relative translational movement of those components. Instead or in addition, the first, second and third conduits 10, 20, 30 and the first and second support members 50, 60 may be interconnected in a manner which restricts rotational movement of one component with respect to another.

The first conduit 10 is fluidly coupled to the second conduit 20 via a first end coupling 15 which fluidly connects the outlet of the first conduit 10 to the inlet of the second conduit 20.

The first end coupling 15 may comprise an injector module 16. The second conduit 20 may be coupled to the third conduit 30 via a second end coupling (not shown) for fluidly connecting the outlet of the second conduit 20 to the inlet of the third conduit 30. Each of the first and second end couplings may define, in combination with its respective support member, a fluid flow path through which exhaust gas may pass between adjacent conduits.

Within the fluid flow path of the emissions cleaning module there may be located a diesel oxidation catalyst (DOC) module, a diesel particulate filter (DPF) module 170, the injector module 16, a mixer module, a selective catalyst reduction (SCR) module and an ammonia oxidation catalyst (AMOX) module.

The DOC module may be located in a first portion of the first conduit 10 towards the first, inlet, end 11 of the first conduit 10. The DPF module 170 may be located in a second portion of the first conduit 10 towards the second, outlet, end 12 of the first conduit 10. The first end coupling 15 may provide a fluid flow path from the second end 12 of the first conduit 10 to the second end 22 of the second conduit 20.

A mixer module may be located in the second conduit 20. The mixer module may be configured to mix a fluid injected by the injector module 16 with a fluid arriving from the first conduit 10. The mixer module may comprise multiple features, such as interspersed fins, which may give rise to an even blend of the injected fluid with the fluid from the first conduit 10. The second end coupling may provide a fluid flow path from the first end 21 of the second conduit to the first end 31 of the third conduit 30.

The SCR module may be located in a first portion of the third conduit 30 towards the first end 31 of the third conduit 30. The SCR module may comprise a catalyst surface intended to catalyse a reaction to occur between the two fluids mixed in the mixer module and output by the diffuser. The AMOX module may both be located in a second portion of the third conduit 30 towards the second end of the third conduit 30. The AMOX module may comprise a catalyst which may catalyse a reaction of one or more of the products output from the SCR module.

The first end coupling 15 may comprise, as shown in FIG. 3, a housing 80 in which a cleaning port may be provided. The cleaning port may comprise an aperture which may be closed by a cover 90. The housing 80 may have a generally tear drop shape in plan view as shown in FIG. 4. The housing 80 may comprise a fixing flange 83 around a perimeter of a lower edge of the housing 80. The housing 80 may be secured to the support member 60 by welding the fixing flange 83 to the face of the support member 60. The housing 80 may be generally domed and may have a wall section 81 which may extend away from the fixing flange 83. The aperture defining the cleaning port may be located in wall section 81. The housing 80 may be provided with an aperture flange 82 which may be upstanding from an edge of the wall section 81 defining the aperture. As shown in FIG. 5, the aperture flange 82 may be outwardly tapered relative to a central axis of the aperture. The aperture in the housing 80 may be circular. Alternatively, it may be generally circular except for one or more flats 140. The shape of the aperture flange 82 corresponds substantially to the shape of the aperture, and in the present case is generally annular.

The cover 90 may comprise a lid section 91 which may have a slightly domed shape as shown in FIG. 4. The cover 90 may have a shape configured to match the shape of the aperture in the housing 80. Thus, where the aperture in the housing 80 is generally circular except for one or more flats 140, the cover 90 will also be generally circular except for one or more flats 150 as shown in FIG. 4. The flats 140, 150 may help to orientate the cover 90 within the housing 80. The profile of the dome may be selected to correspond with the profile of the wall section 81 so as not to disrupt exhaust flow in the first end coupling.

An upstanding cover flange 92 may be provided at a peripheral edge of the cover 90. The upstanding cover flange 92 may also be outwardly tapered relative to a central axis of the aperture such that the taper matches the outward taper of the aperture flange 82 of the housing 80. Consequently, on placement of the cover 90 into the aperture formed in the housing 80, the aperture flange 82 and cover flange 92 may contact one another in a face-to-face arrangement. The tapering of the aperture flange 82 and cover flange 92 may help to prevent the cover 90 passing through the aperture.

An anchor point 100 may be provided on the cover 90, preferably on an outer face of the cover 90. The anchor point 100 may be in the form of a threaded nut which may be welded to the cover 90. The anchor point 100 may be positioned at or near a centre of the cover 90, on or near the central axis of the aperture.

The housing 80 may also provide a mounting for the injector module 16.

On initial assembly of the first end coupling 15, the housing 80 may be formed and the cover 90 may be engaged in the aperture formed by the aperture flange 82. As shown in FIG. 5, a fixative 120, which may be in the form of a weld, may be applied between a rim 88 of the upstanding aperture flange 82 and a rim 93 of the upstanding cover flange 92 to join the cover 90 to the housing 80 in a fixed and possibly sealed manner. The first end coupling 15 may then be assembled with the second support member 60 by welding the fixing flange 83 to the second support member 60. The large end of the housing 80 may be disposed over the opening 61 of the first conduit 10 and the small end of the housing 80 may be disposed over the opening 62 of the second conduit 20.

In use, fluid may be supplied to the emissions cleaning module 1 via an inlet. Fluid may pass into the DOC module in the first portion of the first conduit 10. Prior to receipt at the inlet, the pressure of the fluid may be controlled by a back pressure valve, or engine operating parameters.

The DOC module 170 may comprise one or more catalysts, such as palladium or platinum. These materials serve as catalysts to cause oxidation of hydrocarbons ([HC]) and carbon monoxide (CO) present in the fluid flow in order to produce carbon dioxide (CO₂) and water (H₂O). The catalysts may be distributed in a manner so as to maximise the surface area of catalyst material in order to increase effectiveness of the catalyst in catalysing reactions.

Fluid may flow from the DOC module to the DPF module 170 which comprises features which are intended to prevent onward passage of carbon (C) in the form of soot. Carbon particles in the fluid may thus trapped in the filter. The filter may be regenerated through known regeneration techniques. These techniques may involve controlling one or more of the temperature of the fluid, the pressure of the fluid and the proportion of unburnt fuel in the fluid. Regeneration may also be effected by use of a burner upstream of the DPF module 170.

Fluid may pass from the DOC module 170 past the injector module 16 located within the first end coupling 15. The injector module 16 may be associated with or attachable to a pump electronic tank unit (PETU). The pump electronic tank unit may comprise a tank for providing a reservoir for fluid to be injected by the injector. Such fluids may include urea or ammonia. The tank may comprise a lower portion having a first cross sectional area and an upper portion having a second cross sectional area. The second cross sectional area may be smaller than the first cross sectional area. The difference in cross sectional area between the first and second portions may provide for a volume to house additional components of the PETU. This may provide better protection than if components were simply attached to an otherwise external surface of the tank.

The PETU may further comprise a controller configured to control a volume of fluid to be injected from the tank by the injector. The controller may have as inputs, for example, temperature information and quantity of NO_(x) information which may be derived from sensors in the SCR module.

Fluid may pass from the injector module 16 into the mixer module located in the second conduit 20. The mixer module may comprise features for ensuring that the fluid originating from the first conduit 10 is well mixed with the fluid originating from the injector 16.

Fluid may pass from the injector module 16 into the SCR module located in the first portion of the third conduit via the second end coupling. The SCR module may comprise one or more catalysts through which the mixture of exhaust gas and urea/ammonia may flow. As the mixture passes over the surfaces of the catalyst a may reaction occur which converts the ammonia and NO_(x) to diatomic nitrogen (N₂) and water (H₂O).

Fluid may pass from the SCR module to the AMOX module located in the second portion of the third conduit 30. The AMOX module may comprise an oxidation catalyst which may cause residual ammonia present in the fluid exiting the SCR module to react to produce nitrogen (N₂) and water (H₂O).

Fluid may pass from the AMOX module to the emissions cleaning module outlet located at the second end of the third conduit 30.

In time, it may be necessary to carry out a cleaning operation on the DPF module 170. The cleaning operation may be required after many regeneration events and a significant amount of ash is collected in the DPF module 170 or conduit. The cleaning operation may comprise use of a compressed air blower 110 to direct an energetic jet of air 111 onto a downstream end face 172 of the DPF module 170 which may be used to dislodge some or all of the build-up of particulate matter/ash.

In order to carry out a cleaning operation, the cleaning port may be opened. In order to open the cleaning port, the fixative 120 may be removed by a suitable procedure. Where the fixative 120 is a weld, the procedure may involve cutting, grinding or another suitable mechanism. The cover 90 may now be removed. Removal may be assisted by use of the anchor point 100. For example a threaded rod may be screwed to the anchor point 100 and the threaded rod manipulated to remove the cover 90.

As can be seen in FIG. 6, with the cover 90 removed the aperture provides access for the compressed air blower 110 to be inserted into the first conduit 10 into proximity with the end surface of the DPF module 170. The close proximity of the compressed air blower 110 to the DPF module 170 may increase the effectiveness of the cleaning operation. Preferably a diameter of the aperture is large enough to allow the jet of air 111 to reach at least 90% of a diameter 171 of then end surface 172 of the DPF module 170. More preferably the diameter of the aperture is large enough to allow the jet of air 111 to reach the whole of the end surface 172 of the DPF module 170. Ash may be blown through the entire conduit and removed through the inlet.

On completion of the cleaning operation, the cleaning port may be resealed by replacing the cover 90 within the aperture and applying a new fixative 120, for example, by re-welding the cover 90 to the housing 80.

INDUSTRIAL APPLICATION

The present disclosure provides an emissions cleaning module and method of cleaning a particulate filter of a residue. Providing the cleaning port in the end coupling fluidly connecting the outlet of the first conduit to the inlet of the second conduit allows for improved access and cleaning of the emissions cleaning module. 

1. An emissions cleaning module comprising: a first conduit comprising an inlet and an outlet and containing a particulate filter; a second conduit comprising an inlet and an outlet; and an end coupling fluidly connecting the outlet of the first conduit to the inlet of the second conduit; wherein the end coupling is provided with a cleaning port comprising a cover which closes an aperture in the end coupling.
 2. An emissions cleaning module as claimed in claim 1, wherein the aperture at least partially overlies the first conduit to provide access to the particulate filter.
 3. An emissions cleaning module as claimed in claim 1, wherein the aperture is sized to allow access by a pressurised air blower to at least 90% of an end face of the particulate filter.
 4. An emissions cleaning module as claimed in claim 1, wherein a diameter of the aperture is at least 90% of a diameter of the particulate filter.
 5. An emissions cleaning module as claimed in claim 1, wherein the aperture is surrounded by an aperture flange, and an inner face of the aperture flange is outwardly tapered.
 6. An emissions cleaning module as claimed in claim 5, wherein the cover comprises a cover flange having a taper matching that of the aperture flange.
 7. An emissions cleaning module as claimed in claim 5, wherein the aperture flange is circular.
 8. An emissions cleaning module as claimed in claim 5, wherein the aperture flange is generally circular and is provided with at least one flat or more flats.
 9. An emissions cleaning module as claimed in claim 1, further comprising a fixative between the cover and a portion of the end coupling defining the aperture.
 10. An emissions cleaning module as claimed in claim 9, wherein the fixative is a weld.
 11. An emissions cleaning module as claimed in claim 1, wherein a plane of the cleaning port is substantially perpendicular to a longitudinal axis of the first conduit.
 12. An emissions cleaning module as claimed in claim 1, wherein the cleaning port comprises an anchor point.
 13. A method of cleaning a particulate filter housed in an emissions cleaning module, the emissions cleaning module comprising: a first conduit comprising an inlet and an outlet and containing the particulate filter; a second conduit comprising an inlet and an outlet; and an end coupling at least partially fluidly connecting the outlet of the first conduit to the inlet of the second conduit; the method comprising the steps of: a) providing a cleaning port in the end coupling; b) opening the cleaning port; c) inputting a cleaning fluid through the cleaning port into contact with an end face of the particulate filter; d) recovering residue from the particulate filter; and e) closing the cleaning port.
 14. A method as claimed in claim 13, wherein the cleaning port comprises a cover joined to a remainder of the end coupling by a fixative, and opening the cleaning port comprises at least one of removal and opening of the fixative.
 15. A method as claimed in claim 14, wherein the fixative is a weld and opening the cleaning port comprises removing at least a portion of the weld.
 16. A method as claimed in claim 13, wherein closing the cleaning port comprises welding the cover to a remainder of the end coupling.
 17. A method as claimed in claim 13, wherein the cleaning fluid is compressed air.
 18. An emissions cleaning module as claimed in claim 2, wherein the aperture is sized to allow access by a pressurised air blower to at least 90% of an end face of the particulate filter.
 19. An emissions cleaning module as claimed in claim 2, wherein a diameter of the aperture is at least 90% of a diameter of the particulate filter.
 20. An emissions cleaning module as claimed in claim 2, wherein the aperture is surrounded by an aperture flange, and an inner face of the aperture flange is outwardly tapered. 